California state Sen. Leland Yee leaves federal court in San Francisco in July after he pleaded not guilty to charges including racketeering, bribery, and gun trafficking. (Noah Berger / AP)

Former state Sen. Leland Yee’s campaign committee for last year’s secretary of state race has spent $128,000 on attorney's fees since he was indicted on federal corruption charges, he reported this week.

The practice is legal, but one ethics expert said it should be restricted.

"Unfortunately California's relatively weak restrictions on the use of surplus campaign funds mean that politicians can turn these accounts into personal slush funds," said Sarah Swanbeck, an advocate for the group Common Cause.

"California donors making contributions to a secretary of state campaign, for example, shouldn't have to worry that these well-intended donations can then be used to personally benefit the candidate," she added. "California should seriously consider adopting stricter regulations for how campaign funds [can be] be used."

Yee, a Democrat from San Francisco, dropped out of the race for secretary of state on March 27, a day after he was indicted on charges of accepting $62,000 in campaign contributions in return for favors, and offering to arrange the sale of machine guns and shoulder-fired missiles to an undercover FBI agent posing as a mob figure. Yee has pleaded not guilty to the charges.

Despite dropping out, Yee received some 300,000 votes in the primary.

He was suspended from his position of state senator, but left office in November when his term ended.

A campaign finance report filed Monday indicates Yee's campaign committee spent $68,000 during the last six months of 2014, with about $62,700 going to the law firm of Murphy Pearson Bradley & Feeney and the Sutton Law Firm.

In previous months, Yee's committee paid $76,000 to those law firms, according to campaign reports. As of Dec. 31, his campaign committee still had $294,000 in the bank.

Campaign funds can be used for legal defenses, state officials said. James Lassart, a criminal defense attorney for Yee, did not return calls for comment.